NEW YORK: Researchers have found that a protein that plays a key role in the lives of stem cells can bolster the growth of damaged muscle tissue, a step that could potentially contribute to treatments for muscle degeneration caused by old age and diseases such as muscular dystrophy.

The results, published online by the journal Nature Medicine, showed that a particular type of protein called integrin is present on the stem cell surface and used by stem cells to interact with, or "sense" their surroundings.

The experiment showed that beta one-integrin - one of 28 types of integrin - maintains a link between the stem cell and its environment to promote stem cell growth and restoration after muscle tissue injury.

The researchers found that without this protein stem cells could not sustain growth after muscle tissue injury.

While the presence of beta one-integrin in adult stem cells is apparent, "its role in these cells has not been examined," especially its influence on the biochemical signals promoting stem cell growth, wrote the researchers from Johns Hopkins University in Baltimore, Maryland, US.

In experiments, the researchers injected an antibody to boost the function of the protein into aged muscles to test whether this treatment would enhance muscle regeneration.

Measurements of muscle fibre growth with and without boosting the function of the integrin showed that the protein led to as much as 50-per cent more regeneration in cases of injury in aged mice.

When the same integrin function-boosting strategy was applied to mice with muscular dystrophy, the muscle was able to increase strength by about 35 per cent.